package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import server.util.Context;
import server.util.Host;
import server.util.Mapper;
import server.util.Wrapper;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**定义socket监听的端口号*/
    private int port = 8080;

    private Mapper mapper;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
        //loadServlet();

        loadServer();


        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize =50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/



        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while(true) {

            Socket socket = serverSocket.accept();
//            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            RequestProcessor requestProcessor = new RequestProcessor(socket,mapper);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }



    }


    private Map<String,HttpServlet> servletMap = new HashMap<String,HttpServlet>();

    private void loadServer() {
        // 加载server.xml文件
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();
        mapper = new Mapper();
        Map<String, Host> mappedHosts = mapper.getMappedHost();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            Element element = (Element) rootElement.selectNodes("//Connector").get(0);
            port = Integer.parseInt(element.attributeValue("port"));

            List<Element> hostList = rootElement.selectNodes("//Host");
            for (Element host: hostList) {
                String hostName = host.attributeValue("name");
                String appBase = host.attributeValue("appBase");
                Host mappedHost = new Host(hostName,appBase);
                String hostKey = hostName + ":" + port;
                mappedHosts.put(hostKey,mappedHost);

                // 解析context,，
                // 获取docBase和path,并根据docBase获取应用程序的web.xml路径
                // 针对每个应用程序，生成各自的classLoader
                // 最终将解析好的context放存储到Mapper->mappedHosts->ContextList中
                Map<String, Context> contextList = mappedHost.getMappedContext();
                List<Element> contexts = host.selectNodes("Context");
                for (Element context : contexts) {
                    Context mappedContext = new Context();
                    String docBase = context.attributeValue("docBase");
                    String path = context.attributeValue("path");
                    mappedContext.setDocBase(appBase + "/" +docBase);
                    mappedContext.setPath(hostKey + path);
                    contextList.put(hostKey + path, mappedContext);
                }
                loadServlet(contextList);
            }

        } catch (DocumentException e) {
            e.printStackTrace();
        }finally {
            try {
                resourceAsStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void loadServlet(Map<String, Context> contextList){
        // 加载server.xml文件
        InputStream resourceAsStream = null;
        SAXReader saxReader = new SAXReader();
        Document document = null;
        Element rootElement = null;

        for (Map.Entry<String, Context> mappedContextEntry : contextList.entrySet()) {
            Context mappedContext = mappedContextEntry.getValue();
            String webXMLPath = mappedContext.getDocBase() + "/web.xml";
            try {
                resourceAsStream = new FileInputStream(webXMLPath);
                document = saxReader.read(resourceAsStream);
                rootElement = document.getRootElement();
                // 取得所有的servlet标签
                // <web-app>
                //    <servlet>
                List<Element> list = rootElement.selectNodes("//servlet");
                for (Element element : list) {
                    Wrapper mappedWrapper = new Wrapper();

                    // <servlet-name>lagou</servlet-name> 获取节点以及节点内的文本内容
                    Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                    String servletName = servletnameElement.getStringValue();

                    // <servlet-class>server.LagouServlet</servlet-class> 获取节点以及节点内的文本内容
                    Element servletClassElement = (Element) element.selectSingleNode("servlet-class");
                    String servletClass = servletClassElement.getStringValue();

                    // 根据servlet-name 的值找到url-pattern
                    Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                    String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                    String callPath = mappedContext.getPath() + urlPattern;

                    // 用类加载器加载servlet
                    MyClassLoader myClassLoader = new MyClassLoader(mappedContext.getDocBase());
                    Servlet servlet = (Servlet)myClassLoader.loadClass(servletClass).newInstance();

                    // 加载后的对象封装到Wrapper中
                    mappedWrapper.setServletClass(servletClass);
                    mappedWrapper.setUrl(callPath);
                    mappedWrapper.setServlet(servlet);

                    // 再把 mappedWrapper 保存到 mappedContext 中
                    mappedContext.getMappedWrapper().put(callPath, mappedWrapper);
                }

            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (DocumentException e) {
                e.printStackTrace();
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InstantiationException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 加载解析web.xml，初始化Servlet
     */
    /*private void loadServlet() {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element =  selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());

            }



        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }*/


    /**
     * Minicat 的程序启动入口
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
